1. Field of the Invention
The present invention generally relates to a global positioning system, and more particularly to a crosslinked positioning method for multiple users.
2. Description of Prior Art
Taking a trip or climbing a mountain has become one of the best leisure activities, and thus families, friends, and companies enjoy their getting together for outdoor activities during weekends or holidays. As economy and technology advance, cars are primarily used as a transportation means for outdoor activities, and multiple cars are usually teamed up to form a car team for the activity.
In general, when a car team sets off, each car of the team is equipped with a walkie-talkie or a mobile phone for communications to prevent any car from leaving behind or getting lost, or a satellite navigation system is provided for guiding the cars to the destination. Although walkie-talkies and mobile phones can be used for the coordination among cars, each driver has to watch the rear mirror from time to time and make sure that each car follows closely. If any car is left behind, the car in the front is informed to pull aside of the road and wait for the coming car, or notice the car left behind by walkie-talkies. However, such arrangement is very inconvenient, and may even cause an accident easily. Even though the car left behind can be guided to the destination by a satellite navigation system, the satellite navigation system used in a car usually allows users to locate their own position only, but not the positions of other cars or the distance of their car from others cars of the team.
In addition, disasters in mountain usually occur when a mountain climber gets lost in an unfamiliar mountain path or injured. For disasters in mountain, mountain climbers or victims are unable to inform rescuers immediately or tell the rescuers about their exact location, and they have to wait for rangers to find them after they have not returned at a specific time, and then the rescue team is informed. During a rescue, the rescuers have difficulties of locating the mountain climbers and victims who are in danger, and the rescuers have to search the whole mountain which may take lots of time and delay the time of rescuing the mountain climbers.